Adenovirus vectors have shown promise for vaccines, but one key hurdle is preexisting immunity to these viruses in humans. The VRC has been investigating the use of prime/boost strategies using DNA, nanoparticles, proteins and adenovirus vaccines and the use of alternate adenoviral serotypes or modified adenoviral vectors to overcome prior immunity. During the past year, the VRC has continued to test chimpanzee derived adenoviruses expressing HIV. There is an ongoing on-going study in guinea pigs to test a prime-boost combination of ChAd3 and ChAd63 expressing HIV envelopes. Immune response is currently being analyzed. In addition, studies to evaluate chimpanzee adenovirus vectors (ChAd3 and ChAd63) to analyze their ability to induce an immune response for Ebola and RSV were conducted.